Time delay apparatus



Sept/20,1938. R. A. mmamfs y 2,130,405

TIME DELY )APPARATUS Filed Oct. l0, 1935 E Y BY* INVENTOR /-u. ATTORN EPatented Sept. 20, A1938 uru'rraor STATES TIME DELAY' APPARATUS Rufus A.Andrews, Mount Vernon, N. Y., assignor 4to Ward LeonardElectrlc'Oornpany', a corporation of New York Application octoberv10,1935, semi No. 44,464

(ci. 1in- 1) This invention relates to electrically controlled apparatusapplicable to various uses where after o`ne action occurs, such as theinitial closing of a circuit, a predetermined time interval is to .'ielapse before some other function is to be performed, such as to closeor open another electric circuit or any controlling circuit oi anotherdevice, or to actuate a movable arm, lever, plunger, or perform anydesired operation. l0 One of the objects of the invention is to obtainan improved form of apparatus which will have a high degree of accuracyin thedetermination of the time interval and maintain the same timeinterval under repeated operations in long continued use'. Anotherobject is to provide a device which will be independent of changes oftemperature. Another object isA to obtain a practically instantaneousreset of thev device for repeated use as rapidly as desired. Anotherobject is to produce a device which will be dependable withlong'continued use and of simple and economical construction. Anotherobject is to avoid'the uncertainty and inaccuracy of gearsthrown intoand out of mesh, or the use of clutches and to avoid the excessive wearoccasioned by use of such type of apparatus. Other objects andadvantages of this invention will be understood from the followingdescription and accompanying drawing illustrating a preferred embodimentthereof.

Fig. i is a plan view on the line I--l of Fig. 3;

Fig. 2 is a vertical'section on the line 2 2r of Fig. 1 with certainpa'rts moved to a different position;

Fig. 3 is a vertical section on the line 3 3 of mg. l:

Fig. 4 is a vertical section on the line l-I oi' Pig.' 2;

Fig. 5 is a front elevation ofthe front dial of the device; and

` Eg. 6 is a general diagrammatic representation of certain parts andconnections.

The apparatus shown comprisesv two sheet metal plates-I andl la spacedapart and supported by cross rods 2. On the rear side of platethroughtheplaielandcarriesflxedtoitsinner' end" spur gear-4. This'geardrives 'alargar il gear! which is iournaled on a shaft l which issupported at its rear end in the plate I and at its front end in themiddle inner portion of an adjustable knob 1. This knob is shown in theform of a hexagonal nut cooperating with the dial on the front plate.'I'he knob is journale in the front plate Ia..

Mounted upon the shaft 6 is a differential gear vcomprising the beveledgears 8, 8a and Ib. The

gear 8o'. is fixed to the gear 5 and rotatable therewith on .the shaft6. The gear l is rotatably mounted upon a pin 9 which radially passesthrough an enlarged portion I0 of the shaft i. The gear 8b is secured toa wheel II which is rotatably mounted upon the shaft l. This wheelserves as a brake wheel. The outer periphery of this wheel is milled andis adapted to be engaged by a brake lever for holding the same in fixedposition when desired.

Fixed to the inner end of the knob l is a circular plate I2. 0n theinside of the plate I2 is ixed a housing I3 for a spiral spring I4contained within it. The housing ls in the form of a disc with aninwardly'turned edge which extends over the spring. 'I'Vhe outer end ofthis spring is secured by a pin Ila to the plate I2 or to the iatportion of the housing I3. 'I'he other end e oi the spring Il is xed toa barrel I5 by the pin IIb. I'his barrel has a. disc portion which isrotatable 4on the shaft 6 and an inwardly turned cylindrical 'portionwhich has notches lia formed around its inner edge at regular intervals.A pin It has a threaded engagement with, and extendsradially through,the shaft 6 and is located within the barrel I5. The outer end of thepin It extends beyond the barrel through any desired one of the notchesIta. 'I'his pin serves to transmit the tension of the spring Il to theshaft 6, tending to always turn the shaft 6 in one direction ofrotation. The series of notches IBa permits the tension of this springto be increased or decreased by rotating the barrel I5 while holding theshaft 6 stationary to impose a desired tension upon the spring and thenpassing vthe pin It through one of the notches 'in the adjusted positionand through the shaft I. Fixed to the plate I 2 and extending from theinner face thereof is a pin I1. 'I'his pin extends into the path of thepin I i where it projects beyond the barrel I5. When the knob 1, andvcorrespondingly the plate I2, is adjusted to a desired position, itsimilarly adjusts the position of the pin I1, which position limits theextent of movement of the pin .Il and the shaft l in one direction ofrotation as actuated by the springA Il. Mounted on the rear of thesupport-v ing plate Ia is a strip or plate of sheet metal I3 secured atone end to the plate Ia by a screw |8a. The other end of this stripextends over the edge of the plate I2. A screw |81) passes through theplate Ia from the front and has a threaded engagement at its inner endwith the strip I8 at a point between the plate I2 and the screw |8a. Itis evident that when the screw |8b is tightened, it will clamp the plateI2 in any iixed adjusted'position. A pair of pins I9 extend from theinner face of the plate I2 and are located so that when the plate |2 isturned, one or the other of the pins I9 will engage the edge of theplate I8 and-thus serve as a stop to limit the extreme range of movementof the plate i2.

Fixed to the portion I0 of the shaft 6 is an arm 2U of insulatingmaterial, such as Bakelite, being secured to the shaft by a screw ctpassing through an upturned end of the arm 29. The screw 2da may beextended to form the pin 9 as its opposite end, as shown in the drawing.The present application of theinvention is to the control of an electriccircuit, and for this purpose the arm 2U carries at its outer end across piece 2i of metal having a pair of contacts 2in at its oppositeends on its inner face. These contacts are adapted to engage with acorresponding pair of fixed contacts 22a supported in a fixed positionby metal strips 22 mounted on an insulating cross bar or. plate 23supported by and extending between the plates l and ia. The conductingstrips 22 are provided with holes 22h at their outer ends for connectionto any external circuit to be controlled.

In the path of the end of the arm 20 and between and below the xedconducting strips 22, is movably mounted a conducting stripl 24 whichpasses through a small opening in the insulating plate 23 and is thenbent at right angles and extends downwardly, as shown in Fig. 3. Theinner face of the lower end of the strip 24 carries a contact 24a. Thiscontact is adapted to engage a fixed contact 25 mounted on the plate 23opposite the contact 24a. A pin 26 extends freely through the downwardlyextending portion of the strip 24 and extends also through the plate 23.The pin 2G is headed at its inner end to prevent the pin from passingthrough the plate 23 when the pin is forced outwardly. On the outer endof the pin 26 is a disc 26a having an inwardly turned edge, and asimilar disc 2Gb surrounds the pin 26 and is located at the front of thedownwardly extending portion of the conducting strip 24. A spring 21encircles the pin 25 and extends between the discs 26a and 2Gb. Thisspring tends to force the pin 25 outwardly, the disc 25a. beingprevented from outward movement by a pin 25e passing through lthe outerend of the pin 2E. Normally the spring 21 thus tends to force thedownwardly extending portion of the conducting strip 24'inwardly so asto cause contact 24a to bein engagement with fixed contact 25. If,Ahowever, the inwardly extending end of the strip 24 be depressed, thedownwardly extending portion of the strip 24 will be moved outwardlyagainst .the pressure oi the spring 21 and the circuit will be openedbetween the contacts 24a and 25. The strip 24 is electrically connectedby a lead 24h which is soldered thereto, to one lead of the electricdriving motor 3; and the'contact 25 is connected by a lead 25a to oneside of the supply circuit of the motor. Thus when the contacts 24a and25 are in engagement, the motor circuit will be closed provided themotor circuit is othervpassing loosely through the strip 2|.

wise closed; but when the inner end of the strip 24 is depressed, themotor` circuit will be open.

The inner end of the strip 24 is in the path of movement of the arm 20;and when this arm is driven to its final position by the motor 3, itengages the inwardly projecting end of the strip 24 and depressesit toopenthe contacts 24a and 25, thus opening the motor circuit kat thecompletion of 'its function. The arm 20, in moving to its limitingposition, causes the cross strip 2| carried by the arm to engage thefixed contacts 22a before the stripv 24 is engaged by the arm 20. Inorder to .permit the arm 20 to continue its movement toengage the innerend of the strip 24, the cross strip 2| is yleldably mounted on the topof the arm 20 by a pin 28 fixed to the arm 20 and Between the strip 2|and a disc 29 retained in place by a pin 28a passing through the outerend of the pin 28, is located a spiral spring 30 which surrounds .thepin 28. Thus this spring tends to normally hold the cross piece 2|against the arm 2l).

When, however, the cross piece 2| is swung over by the arm 2|! to engagethe contacts 22a, 4the cross strip 2| is permitted to yield and move upwardly on the pin 28 while still maintaining engagement with thecontacts 22a. This permits the arm 20 to continue its movementsuiiiciently to engage the inner end of the strip 24 and open thecircuit of the motor, as already described.

The brake for holding the brake wheel in xed position when desired isactuated by an electromagnet 3| mounted on an inwardly extending portionIb of the plate I. A strip 3|a of magnetic material extends from thelower end of the core of the magnet 3| upwardly at the side of the coilof the magnet. Movably mounted on the upwardly kextending end of themagnetic strip :ila` is an armature 3Ib which extends over the upper endof the core of the magnet 3|. A strip 32 is secured to one end of thearmature 3|b and has an extension 32a therefrom. A spring 33 isconnected at one end to this extension and at the other endto anextension 34a from a strip 34 clamped between the lower portion of themag- A rod 35 passes loosely through the projecting end of the strip 35and a pin 36a is passed vthrough the upper end of the rod 36'above thestrip 35 for supporting the end of the rod by the strip. The lower endof the 'rod passesl loosely through the brake bar 31. This bar extends'over the brake wheel I I and is pivotally mounted at the opposite endfrom the connection of the rod 35 on a pin 33 projecting from andsupported by the plate Ia. lThe brake bar is supported in relation tothe brake wheel so that when the bar is forced downwardly by the rod 36it will press against the brake wheel and thus hold the wheel in fixedposition. At the upper end of the rod 3B is a spiral spring 38h whichencircles the rod. The upper end of the spring is seated in a shallowmetal cup 35e located on the lower side of the extended portion ci strip35. The lower end of the spring is seated in a similar cup 36d which isretained from downward movement on the rod by a pin 36e passing throughthe rod.

When' the amature SIb is attracted by the controlling magnet 3|, thestrip Il will `cause a downward movement of the rod by the strip beingforced downwardly against the spring which in turn exerts a downwardpressure on the pin "e and thus causes a downward. movement of the rod.Before the amature of the magnet has completed its movement to 'its nalvattracted podtion, the brake bar will engage the circumference of thebrake wheel I I; and in the further movement of the amature. the springb will be somewhat compressed. 'I'his insures the application of apredetermined and sufilcient pres'- sure of the brake bar 31 against thebrake wheel.

Fig. 6 shows the connections of the parts, there being a main closingswitch V39 between the source Il and the controlling apparatus. Themagnet II is connected acro the supply wires so as to be controlled bythe switch 3l and also when desired by switch 4I in the magnet circuitfor controlling this circuit independently of the motor circuit. Theelectric motor is connected across the supply wires through the switch24 when engaging the contact 2B and this switch is beyond theconnections of the magnet Il so that whenthe strip or switch 24 isopened, it will not open the circuit of the magnet 3|. Another switch 42-is shown in series in the motor circuit which may be used when desiredfor controlling the motor circuit independently of the magnet circuit.

On the face of the plate Ia is mounted a dial plate having a circularscale o concentric with the aids of the knob 1. Thisscale may begraduated in seconds or any other time intervals desired, depending uponthe design and purpose -of the apparatus. An arrow 1a is marked on theface of the knob 1 to cooperate with the scale for securing any desiredtime interval setting. f

In operation, the screw IIb will be loosened for permitting adjustmentof the plate I! to attain any predetermined time interval of operationby turning the knob 1 to the proper setting. The screw IIb is thentightened to hold the plate I2 in fixed position. In making thissetting, the pin I1 has been adjusted to a certain position which, byits engagement with the pin III, causes the shaft 6 ofthe mechanism toassume `a certain initial position. The' initial position of the `shaftwill always correspond to the adjusted position of the pin I1 because'the spring Il always tends to actuate the shaft and the pin It in adirection to cause the latter to engage the pin I1. In making thisadjustment of the initial position of the shaft 0 it necessarily followsthat the control arm 20 is moved by the shaft to assume its initialposition at some point which is at a predetermined angular position fromthe fixed contacts 22a. In Fig. 1 the arm 20 is shown at about 180from-a plane passing Athrough the contacts 22a and through the axisswitch Il. 'I'he contact strip 2l is then in en- Agage'ment with the xedcontact 2l by reason of being closed by the action of spring 21 asalready described. The clodng of the line switch l! energiaes the magnetSI which attracts its armature IIb downwardly and moves the brake barI1- downwa'rdly to engage and hold brake wheel II in fixed position asalready explained. The closing of the line switch also starts the motorto drive the gear 8a in one direction of rotation. In view of the brakewheel II and its bevel gear Ib being held in fixed position at thistime, the rotation of the gear la will cause the rotation of the gear lon its pin support. On account of the gear Ib being held stationary, itresults that the shaft 6 is turned by the gear 8 being forced to travelaround the gear lb. The direction of rotation ofthe gear la is such asto cause the shaft I and-its arm Ilto be moved in a direction toapproach the flx'ed contacts 22a. The driving movement continuesresulting in the t cross piece 2| first engaging the contacts 22a andthen, as already explained, causing the arm 2l to engage the contactstrip 2l and open the circuit oi' the motor. This stops the motor andprevents any further supply of energy thereto. The arm 2l and thedifferential gear remain in their final position, however, because themagnet 3i continues to be excited holding the gear Ib in position. 'I'hebevel gear la also remains in fixed position because friction and thetrains of reduction gearing prevent the motor from movement.

After the movement of the controlling arm 20 has accomplished itspurpose the line switch 39 may be opened. The controlling arm 2li willthen immediately snap back to its initial position because the releaseof the brake wheel II by the magnet permits this wheel to revolve freelyand the spring I 4 which is always exerting its tension on the shaft ispermitted to act to rotate the shaft I. The rotation of this shaft bythe spring causes the differential gear 8k to travel back aroundstationary gear la, permitting the return of the parts to their initialpositions. Upon again closing the line switch 3l, the operation may berepeated in the manner just described and this repetition may occur asoften as desired. l

It is evident that by reason of the motor I, being a synchronous motorand by reason of the frequency of theusual alternating current supplylines being kept substantially constant, the time required for the motorto drive the parts from their initial position to their final position,will always be substantially the same. If it be desired that the timeinterval between the closing of the line switch 3S and the attainment ofthe final position of the arm 20 be changed to any other desired timeinterval, the knob 1 will be ad- .iusted in the-manner already describedto give the desired time interval by a proper new location of the pinI1. Thus, a wide range of predetermined time intervals may be obtainedby a simpleand /conven'ient adjustment.

'I'he adjusted tension of the spring I 4 does not affect the timeinterval of the sequence of operations because that is determined by theconstant speed of the driving motor. The tension of the spring Il doesaffect the time of snapping the parts back to their initial position andthis ten# sion may be such as to make the return of the partssubstantially instantaneous. 'Ihe apparatus is not subject to anymaterial wear under; long continued use because as regards the brake,

there is no appreciable friction wear vbecause the l brake bar engagesthe brake wheel quickly before there is any appreciable torque exertedby this wheel; and as regards the gearing there is no appreciable wearbecause Athe gearsare always in mesh and there is vno shifting of theparts or uncertainty of engagementof shiftable parts.

. In some applications of the invention the motor 3 maybe started beforethe circuit of the brake magnet is closed. In such a case the switch Ilwill first be opened and the motor started by closing the switch I2,assuming the line circuit fto be closed. With the magnet circuit openand .the motor running, the control arm 2l remains in its initialposition and the bevel gear 8b and brakewheel are loosely driven in adirection reverse to that o! gear 8a. Upon closing switch 14| the brakewheel and gear 8b' are held in xed position and the operation of theparts occurs in the manner already described, the time delay intervalelapsing after the closing of switch 4i. Upon again opening brake magnetswitch 4|, the control arm 2li will automatically be returned to itsinitial position, even though the motor resumes its rotation upon theautomatic closing of contact strip 24, as the brake wheel is then treeto turn idly. indeed the motor circuit may re main closed continuouslyand the time delay action initiated by the closing of brake magnet cir1cuit and obtaining reset by opening the brake magnet circuit.

In some cases, instead ci using an alternating current synchronousmotor, a constant speed direct current motor may be used supplied from acircuit of substantially constant voltage; and it will be understoodthat various modifications and various applications of this inventionmay be made without departing from the scope thereof.

I claim:

1. Time delay apparatus comprising a driven element to be moved from aninitial position to a final position, a circuit to be controlled,differential gearing for driving said element, an electric motor fordriving said gearing in one direction, electromagnetic means forcontrolling the movement of one of the gears of said gearing,

a switch for closing thecircult of said means, a switch for closing thecircuit of said motor biased to closed position, means successivelyengaged by said driven element and controlled thereby for firstail'ecting the connections of said circuit to be controlled and thenopening said second named switch upon said element attaining its finalposition, and a spring for returning said element to its initialposition upon the subsequent opening of said first named switch.

2. Time delay apparatus comprising a driven element to be moved from aninitial position to a final positon, a. circuit to be controlled,differentialv gearing for driving said element, an electric motor fordriving said gearing in one direction, electromagnetic means for holdingstationary one of the gears of said gearing, a switch for closing thecircuit of said motor and of said means, a switch for closing thecircuit of said motor biased to closed position, means successively en-Haged by said driven element and controlled thereby for rst affectingthe connections of said l circuit to be controlled and then actuatingsaid Second named switch for opening thecircuit of the motor upon saidelement attaining its final position, and a spring for returning saidelement to its initial position upon the subsequent opening of saidfirst named switch.

3. Time delay apparatus comprising a driven element to be moved from aninitial position to a iinal positon, diilerential gearing for drivingsaid element, an electric motor for driving said gearing, meanscomprising a. magnet for holding stationary one of the gears of saidgearing, means for closing the circuit of said motor and of said magnet,circuit controlling means actuated by said element upon its attaining acertain position,

a spring for returning said element to its initial position upon openingthe circuit of said magnet, a projecting element movable with saiddriven element, a stop engaged by said projecting eienient for limitingthe initiai position of said driven element, and movable means foradjusting the position of said stop, said spring having one end thereofmechanically connected with said movable means.

4. Time delay apparatus comprising a driven element to be moved from aninitial position to a flnai position, diierential gearing for drivingsaid eiement, an electric motor for driving said gearing, meanscomprising a magnet for holding stationary one of the gears of saidgearing, means for ciosing the circuit of said motor and of said 130magnet, circuit controlling means actuated by said element upon itsattaining a certain position, a spring for returning said element to itsinitial position upon opening the circuit of said magnet, a projectingelement movable with said driven element, a stop engaged by saidprojecting element for limiting the initial position of said drivenelement, and means for adjustably connecting one end of said spring tosaid projecting element.

5. Time delay apparatus A4comprising a driven element to be moved froman initial position to a final position, differential gearing fordriving said element, an electric motor for driving said gearing, meanscomprising a magnet for holding driven element, movable means foradjusting the position of said stop, said spring having one end thereofmechanically connected with said movable/means, and means for adjustablyconnecting the other end of said spring to said projecting element.

RUFUS A. ANDREWS.

